Heat pump system



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HEAT PUMP SYSTEM 9 Sheets-Sheet 6 Filed April 20, 1953 William F30 Mac PM @P wa I v, I l|\\\\\\| :Illllllll I k 1 1 I- I lll I I lll I: I I I I I I I I I ll! I I .Q% \u 9m mum w m P W NW WWN June 12, 1956 w. F. BORGERD ETAL 2,749,724

HEAT PUMP SYSTEM 9 Sheets-Sheet 7 Filed April 20, 1953 June 12, 1956 w. F. BORGERD ETAL 2,749,724

HEAT PUMP SYSTEM Filed April 20. 1953 9 Sheets-Sheet 9 Eazil.

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HEAT PUMP SYSTEM William F. Borgerd and Mack M. Jones, Evansville, Ind., assignors, by mesne assignments, to Whirlpool-Seeger Corporation, a corporation of Delaware Application April 20, 1953, Serial No. 349,594

19 Claims. (Cl. 62-129) This invention relates generally to heat pumps and more specifically to an improved residential heat pump wherein the change from the cooling function to a heating function is affected by a switching of the flow of the refrigerant only.

A number of systems utilizing evaporative refrigeration units for heating as well as cooling an enclosed living space are well known in the art.

One of these systems involves a mobile mounting of the evaporative refrigeration unit in cooperation with an enclosed living space so that the evaporator of the refrigeration unit is selectively positionable Within or without the enclosed living space, and whereby the condenser of the refrigeration unit will be positioned without or within the enclosed living space respectively. When the evaporator is positioned within the living space, the 9 living space is being cooled, and when the condenser is positioned within the living space, the living space is be ing heated.

Another of these systems involves adjustable duct work mounted in cooperation with the evaporative refrigeration unit, so that the duct work is selectively adjustable to complete an air circuit including the air of the enclosed living space and an air circuit over either the evaporator or the condenser of the refrigeration unit.

Another of these systems involves a heat transmitting liquid circuit which is in an intimate heat transfer relationship with the enclosed living space and which also is selectively adjustable to an intimate heat transfer relationship to either the evaporator or the condenser of the refrigeration unit.

Another of these systems involves duct work mounted in cooperation with an enclosed living space and with a heat exchanger, which may become either an evaporator or condenser of the refrigeration-unit depending upon the selective operation of means for reversing the direction of flow of the refrigerant in the refrigeration unit.

There are advantages and disadvantages to each of the above described systems. For example, the first system is simple in theory, but is impractical in most instances in that the equipment necessary for mobilizing the refrigeration unit is cumbersome'and complicated. The second system requires complicated and expensive duct work for an efficient system and reduces the percentage of the entire system that may be manufactured in a factory as a unit. The thirdsystem requires expensive and complicated valves and plumbing work for the heat transmittingliquid, and also reduces the percentage of the entire system that may be manufactured in a factory as a unit. The fourth system requires substantially less valves, plumbing and duct work than the above described second and third systems. Further, the fourth system may be constructed as a substantially less cumbersome and more compact system than the above described first system. Additionally, substantially more of the fourth system may be manufactured in a factory as a unit than any of the other described systems. This invention is concerned with the above described fourth system, and is an improved arrangement of such a system. It is therefore an object of this invention to provide an improved heat pump that will heat or cool an average residence with an efficiency substantially equal to the efficiency of conventional heating and cooling systems.

It is another object of this invention to provide a heat pump having an evaporator, a condenser, and refrigerant switching means for changing the flow of refrigerant through the evaporator and the condenser, so that the flow of the refrigerant can be switched, whereby the evaporator becomes a condenser and the condenser becomes an evaporator.

It is another object of this invention to provide a heat pump as a compact unit, whereby the heat pump may be easily mounted to occupy a small portion of a residence.-

it is another object of this invention to provide a heat pump having a number of independent air circulation circuits which will increase the efficiency of the heat pump.

It is another object of this invention to provide a heat pump which may be easily switched from one function to another, and to provide in such a pump, means for preventing liquid refrigerant from being sucked into the compressor when the function of the heat pump is changed.

It is another object of this invention to provide a heat pump which will efiiciently operate with capillary tubes as metering devices for the heat pump.

It is a further object of this invention to provide a heat pump which is substantially assembled at a factory as a completed package, whereby a hermetic refrigerant circuit is provided.

It is a feature of this invention that two separate liquid circuits are provided. One of the liquid circuits beinga water-alcohol mixture disposed within a tubing system including heat exchangers within the residence, and ground coils disposed within the ground about the residence. The other liquid being a standard liquid refrigerant disposed within a tubing system including the mentioned heat Figure 2 is a front elevational view of the heat pump cabinet with the front covers removed;

Figure 3 is a right side elevational view of the heat pump cabinet shown in Figure 2 with the side cover removed;

Figure 4 is a top plan view of the heat pump cabinet shown in Figure 2 with the top covers removed;

Figure 5 is a partial left side elevationalview of the heat pump cabinet shown in Figure 2;

Figure 6 is a diagrammatic view of the heat pump operating on the cooling cycle;

Figure 7 is a diagrammatic view of the'heat pump operating on the heating cycle;

Figure 8 is a diagrammatic view of the ground coil liquid circuits;

Figures 9 and 10 are side and front elevational views respectively of the main heat exchanger between the ground coil liquid circuit and the refrigerant circuit, and

Figures 11 and 12 are front and side views respectively of the sub-cooling heat exchanger between the ground coil liquid circuit and the refrigerant circuit.

The present embodiment is the preferred embodiment but it is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of this invention.

For a general descripion of this invention reference is 3 madeto Figure 1 wherein a cross section of the residence is shown. The heat pump is mounted in the basement of the residence, but it is to be understood that the invention may be modified so that the heat pump can be mounted in a room separate from the main living space, such as a utility room of a residence without a basement. The residence comprises an attic12, a main living space 11, and an auxiliary living space or basement 13. The basement 13, as can easily be seen in Figure l, is positioned substantially within the ground 14, so that under normal circumstances the heat or cooling load of the basement 13 will not be great, due to the insulating efiect of the ground 14. For purposes of simplicity the heat pump proper may be said to comprise three main sections, 16, 17 and 18. The section 18 has Openings at the top and bottom thereof. A fan and a heat exchanger are mounted within the section 18 between the openings therethrough. The fan is a propeller type and is operated by a small motor. A small fan motor is used because the resistance to air passing through section 18 is low since no ducts are connected to this section and no air filter is used. Thus this fan, when operating, efiiciently moves a large volume of air through the heat exchanger disposed within the section 18 to cause a circulation of the basement air. rated from the air within the main living space 11. The detailed structure and operation of the section 18 will be described below.

The suction 16 has a duct system connected thereto by some means such as canvas boots. As is Well known in the art, the canvas boots will prevent vibrations present in section 16 from being transmitted to and through the duct system. One duct of the duct system is connected to the top of section 16 and from there leads into the main living space 11. Another duct 24 of the duct system, leading from another part of the living space 11, is connected to the lower portion of the section 16. A main heat exchanger and a centrifugal fan are mounted within the section 16 to cause a circulation of air throughout the duct system and the living space 11. The detailed structure and operation of section 16 will be described below.

The section 17, which is shown diagrammatically as two sections, comprises two heat exchangers and a liquid circulating pump. As can easily be seen in Figure 1, ground coils 26 are provided, which are buried without the residence in the ground 14, and which are connected by the tubes 27 to the section 17. The tubes 27 are connected to the heat exchangers and to the circulating pump within the section 17. A liquid, such as a water-alcohol mixture, is disposed within and completely fills the ground coils 26, the tubes 27, the liquid circulating pump and the heat exchangers within the section 17. Because the temperature about the ground cooling coils 26 may vary over a range of 70, means must be provided for permitting an expansion and contraction of the water-alcohol within the water-alcohol circuit. This means comprises an expansion tank 19 mounted above the section 17 near the ceiling of the basement 13. The expansion tank 19 is connected into the water-alcohol circuit by means of the flexible tubing 20. The top of the expansion tank 19 is vented, thereby permitting an expansion and contraction of the water-alcohol within the water-alcohol circuit. The detailed structure and operation of the section 17 will be described below.

Further, as seen in Figure l, a drain 22 is provided which is positioned adjacent a sewer 23. The drain 22 is connected into the base of sections 16 and 18 so that any condensate formed within the heat pump during the cooling cycle thereof will be disposed of through the drain 22.

For a detailed description of the structure of the heat pump proper, reference is first made to Figures 2 through 5. The various portions of the heat pump proper are moutned within a frame 30. This frame may be constructed by any means well known in the art. To the The basement air is substantially scpavarious sides of the frame 30, panels are removably mounted .to enclose the heat pump proper. As is well known in the art, the frame 30 or portions thereof and the panels may also be formed as unitary structure. The portion of the heat pump noted above as substantially comprising section 18 will be described in detail first.

Three vertically disposed walls, 31, 32 and 33, separate the section 18 from the rest of the heat pump, as can easily be seen in Figures 2 and 4. Two opening are provided in the left side of the heat pump cabinet. A heat exchanger 34 is mounted in cooperation with the lower opening in the left side of the heat pump cabinet. The heat exchanger 34 may be of any type well known in the art. Specifically, the heat exchanger 34 comprises a plurality of vertically disposed cooling fins, and a plurality of horizontally disposed tubes. Adjacent ones of the horizontal tubes are interconnected in groups to form a group of eight separate continuou lengths of tubing with the ends of each length of tubing terminating at opposite sides of said heat exchanger 34. The heat exchanger 34 will be designated as the basement air coil 34. Behind the basement air coil 34, and within the section 18 a plurality of balancing receivers 35 are mountedi The balancing receivers are mounted within the section 18 in order that in some measure they may erform the function of heat exchangers in the basement air circuit. However, if desired, they may be positioned partially through or completely on the other side of the wall 33. Each of the balancing receivers 35 comprises a longitudinal container of a certain volume, the certain volume of each receiver 35 will be described below. These balancing receivers 35 are eight in number. One balancing receiver 35 is associated with each length of tubing of the basement air coil 34. Each of the balancing receivers 35 is mounted in a sloped position. The lower ends of each of the balancing receivers 35 are connected by means of tubings 36 to the ends of one of said separate tubings of the basement air coil 34. The upper ends of each of the balancing receivers 35 are connected to one of the lengths of tubing 37, which are mounted through the wall 31 of the section 18. The lengths of tubing 37,

are connected to the structure which will be described below. The other ends of the separate tubings 36 of the basement air coil 34 are each connected to a separate capillary tube 143 through the wall 31 of the section 18. The remaining structure disposed within the section 18 comprises a fan 38 and a fan motor 39. The fan 38 is mounted within the upper opening in the left side wall of the heat pump cabinet. The fan motor 39 which drives the fan 38 is mounted through the vertical wall 33 of the section 18 in a well 29, as can be easily seen in Figures 2 and 4. it is intended that the fan 38 be of the propeller type, Well known in the art, and that the fan motor 39 be of a small horsepower. For example, it has been found that a fan motor 39 of ,5 horsepower is sufiicient to provide the proper circulation of air in the average basement. It can thus be seen that when the fan 38 is operating, air is drawn into the section 18, through the tins of the basement air coil 34, upward through the section 18, and out of the section 18 through the upper opening in the left side of the heat pump cabinet.

To next describe the detailed structure approximately enclosed by the afore-mentioned section 16, reference is made to Figures 2, 3 and 4. In the lower front right portion of the heat pump cabinet, a compressor 40 is mounted. This compressor 40 includes a motor for the operation thereof and is constructed as a hermetic unit. The detailed structure of the motor-compressor unit is not shown as these units are known in the art. In order that the compressor 40 may be cooled to prevent overheating thereof, a water jacket is provided about the compressor 4t Inlet tube 42 and outlet tube 41 is provided to the water jacket. The compressor 40 is mounted upon a stand 43 in any conventional manner. The compressor 4-0 mounting also includes resilientmembers 44 to prevent the transfer of any vibrations of the compressor to the base of the heat pump cabinet. Mounting means and 46 further support the compressor 40. The compressor 40 is further provided with an inlet tube 47 at the top thereof, and an outlet tube 48 at the bottom thereof, as can easily be seen in Figures 2 and 3.

Section 16 is further provided with a refrigerant reversing valve 50, which may easily be seen in Figure 2. The valve 50 may be of any type well known in the art; however, for purposes of explanation a manually operated type is shown partially diagrammatically. The valve 58 may be divided into two portions for a description thereof, the lower portion 51 and the upper portion 52. The lower portion 51 is a hollow body portion and has five ports therein, 56, 55, 57, 58, and 59. Between adjacent ones of these ports, four valve seats 60, 61, 62, and 63 are disposed. A shaft 54 extends longitudinally through the center of the lower portion 51, and has two valve heads 64 and 65 rigidly mounted thereto. The valve shaft 54 is connected to cam means (not shown) disposed within the upper portion 52 of the valve 50. A handle 53 is also connected to the cam means within the upper portion 52, so that the valve shaft 54 is selectively movable to either of two positions by a manual operation of the handle 53. One of these positions is shown in Figure 2. In this position the valve head 64 is seated against the valve seat 60, and the valve head 65 is seated against the valve seat 62. Thus, ports 59 and 58 are interconnected, and ports 55 and 57 are interconnected, through the interior of the lower portion 51 of the valve 50. If the handle 53 is moved to the other operated position as indicated by the notch in a portion of the upper portion 52 of the valve 50, the valve shaft 54 will be moved so,

that the valve head 64 will be seated against the valve seat 61 and the valve head 65 will be seated against the valve seat 63. When the valve has been operated to this,

position, ports 55 and 56 will be interconnected through the body portion 51, and ports 57 and 58 Will be inter-,

connected through the body portion 51 of the valve 50. Port 58 of the valve 50 is connected by a tube 67 to the outlet 48 of the compressor 40. Port 55 of the valve 50 is connected by a tube 66 to the inlet 47 or suction line of the compressor 40. A header 68 interconnects ports 56 and 59 of the valve 50.

The afore-mentioned heat exchanger of compartment 16 will be designated as the main air coil 70. This coil 70 which may be seen in Figures 2, 3, and 5 is positioned at the rear of the heat pump cabinet, and occupies the lower half of the heat pump cabinet. It is intended that the rear side of the main air coil 70 be connected to the return duct from the main living space, such as the duct 24 in Figure 1 described above. The main air coil 70 comprises a group of eight continuous lengths of tubing. Each length of tubing is convoluted horizontally cross the width of the coil 70, and the ends of each length of tubing terminate at the left side of the heat pump cabinet as can easily be seen in Figure 5. The main air coil 70 further comprises a large number of vertical fins which are mounted in good thermal contact with the eight lengths of tubing. One end of each of said lengths of tubing of the coil 70 are connected into a header 71 which may be seen in Figure 5. The open end of the header 71 is connected to a length of tubing 72 which is partially shown in dotted lines in Figure 5. The remainder of the tubing 72 may be seen in Figure 2, wherein the tubing 72 is shown as being connected into the header 68 which was described previously as being associated with ports 56 and 59 of the reversing valve 50. The other ends of the eight lengths of serpentine tubing of the main air coil 70 are connected to the eight lengths of tubing 37, which have been described previously as being connected to the upper ends of each of the eight balancing receivers 35 through the vertical wall 31 of the section 18. Between the back of the main air coil 70 and the rear edge of the heat pump cabinet, an air 6 filter 73 is postioned. The air filter 73 may be removed from the right side of the heat pump cabinet for cleaning or replacement thereof. The air filter 73 may be of any type well known in the art.

The afore-mentioned fan within the section 1 6 is mounted in the central upper portion of the heat pump cabinet. This fan is designated with the numeral and is of the centrifugal type, well known in the art, wherein air is drawn into each side 81 of the fan 80 and into the fan rotor 83, through the rotor 83, and out of the top 82 of the fan 80. It is intended that the intake duct to the main living space be mounted over the top 82 of the fan 80, for example, as the previously described duct 25 of Figure 1. The fan rotor is rigidly mounted to a shaft 84. A pulley 85 is also mounted on one end of the shaft 84, whereby a rotation of the pulley 85 causes an operation of the fan 80. The shaft 84, including the fan rotor 83 and the fan pulley 85, is rotatively mounted to an assembly which will minimize any vibrations of the fan 80. The fan housing is fixedly mounted to a portion of this assembly. This assembly comprises two bearings 86 through which the shaft 84 is rotatively mounted, and the frame of the assembly indicated generally with the numeral 87. The frame 87 comprises three U-shaped supporting elements 88. The ends of each of the U-shaped elements 88 are rigidly attached to the bearings 86 and are positioned at various angles to each other as can easily be seen in Figure 3. Braces 89 mounted between the U-shaped elements 88 maintain these elements in their angular arrangement. A pair of legs 90 are rigidly attached to one of the U-shaped elements 88 as can be seen in Figures 2 and 3. A second pair of legs 91 are rigidly attached to the rearwardly, of the heat pump cabinet, positioned U-shaped element 88 as can be seen in Figure 3. Each of the legs of the pairs of legs 90' and 91 are mounted upon a shock absorber 92, such as a block of rubber, which is in turn connected to the frame members of the frame 30 of the heat pump cabinet. The fan housing has a pair of brackets 160 mounted on each side thereof, and one bracket of each pair is resiliently mounted to the forwardly positioned element 88, and to the other bracket of each pair is resiliently mounted to the rearwardly positioned element 88. The means for operating the fan 80 comprises a motor 93. The motor 93 includes a liquid pump mounted therewith as a unitary structure at the left end thereof. The operation of the pump will be described below. For the mounting of the motor 93, a bracket 94 is provided. One end of the bracket 94 is rigidly attached to the top of the motor 93 as can be seen in Figure 3. The other end of the bracket 94 is formed to include a bearingand is positioned about the center one of the three U-shapedelements 88, as can be seen in Figure 3. Thus, the motor 93 is pivotally mounted about the center one of the three U-shaped elements 88. Further, a pulley 95 is mounted to the end of the armature shaft of the motor 93. A fan belt 96 is then positioned over the pulleys 85 of the fan 80 and 95 of the motor 93. The bracket 94 and the fan belt 96 will then maintain the motor 93 properly positioned, and the weight of the motor 93 upon the fan pulley 95 will mtaintain proper tension upon the fan belt 96. If it is found that the weight of the motor is too great, a coiled spring can be connected between point 97 on the bracket 94 and point 98 on the rearward U-shaped element 88 to reduce the weight of the motor 93 bearing upon the fan belt 96. Since the motor 93 is supported by the assembly 87, the shock aboserbers 92 will also prevent any vibrations of the motor 93 from being transmitted to the heat pump cabinet. It thus can be seen that if the motor 93 is operated to operate the fan 80, air will be drawn through the main air coil 70, through the interior portions of the heat pump cabinet, upward and into the sides 81 of the fan 80, through the rotor 83 of the fan 80, and out of the top 82 of the heat 7' pump cabinet. Assuming that the heat pump is connccted into a system such as shown in Figure 1, it can then be seen that when the motor 93 is operating, air will be circulated through the main air coil 7% and the main living space 11.

To next describe the structure of tie aforementioned section 17, reference is made to Figures 2, 3, 4, 9, 10, 11 and 12. importantly, this section comprises a submerged coil 100. The submerged coil 1% is mounted within the heat pump cabinet at the rear thereof, and occupies the upper half thereof and the entire width thereof. The submerged coil 1% is completely insulated on all sides by insulation 101. For a detailed description of the con struction of the submerged. coil 1110 reference is specifically made to Figures 9 and 10. Four separate sections of serpentine tubing 162 are provided, which are positioned one above the other in vertical alignment. Each section of serpentine tubing 1&2 has plurality of straight horizontal portions interconnected by curved end portions. The embodiment disclosed in Figures 9 and 10 shows eighteen straight portions to each section of serpentine tubing 1112. The eighteen straight portions are connected in three groups to the short headers 119 and 120. Thus, each section 102 comprises three parallel runs or lengths of serpentine tubing. In order that a liquid may be circulated about the sections of serpentine tubing 102, they are enclosed within a casing which comprises front wall 1113, rear wall 1517, end walls 194, top wall 105, and bottom wall 166. Front wall 193 and r r wall 107 are curvilinear or corrugated when viewed along a vertical plane such as in Figure 9, to conform to the spacing and placement of the various straight sections of the sections of serpentine tubing 1112. The space defined by the described walls is divided into three compartments by the vertical walls 109 and 1111. Within each compartment are anumber of spaced apart vertical dividing walls 1128. Each of the walls 168 has an opening at one end thereof. The openings in the walls 188 are so positioned that adjacent walls 111% have the openings at the opposite ends thereof. Thus, it can be seen that a liquid may be circulated up one wall 108, through the opening therethrough, down that wall 168, and through the opening in the adjacent wall 168, up that wall 1118, through the opening in the next adjacent wall, and thereon through the entire compartment. The separate lengths of serpentine tubing extend through and are in good thermal contact with the walls 108, 109, and 111). Two headers provide inlets and outlets to the three compartments. Header 111 serving as an inlet to the three compartrnents, and header 112 serving as an outlet from the three compartments. Tube 113, connected to the header 111, serves as an inlet for the first compartment. Tube 114, connected to the header 111, serves as an inlet for the middle compartment, and tube 115, connected to the header 111, serves as an inlet to the third compartment. Tube 116, connected to the header 112,, serves as an outlet from the first compartment. Tube 117, connected to the header 112, serves as an outlet from the middle compartment, and tube 118, connected to the header 112, serves as an outlet for the third compartment. Thus, it can be seen that if a liquid line is connected the header 111, the liquid will simultaneously flow into the three compartments of the submerged coil 1%, will circulate through the various walls 1&8 of the coil 1-911, meanwhile causing a heat transfer between the separate lengths of serpentine tubing 1G2 and the liquid flowing through the three compartments of the coil 1119:, and the liquid will then flow out of the header 112. In order that the submerged coil may be filled with a liquid through means other than the header 111, a capped filler tube 21 is provided at the top of the first compartment of the submerged coil 1410. In order that expansions and contractions of the liquid Within the compartments of the submerged co-il 1110 and throughout the remainder of the circuit including the submerged coil 1% may be permitted, small tube 219 is provided at the top of the submerged coil 1%. The tube 20 is connected into the middle compartment of the coil 1011. It is intended that the tube 20 be connected to a vented expansion tank such as is shown in Figure 1. When the submerged coil 1% is mounted within the heat pump the capped filler tube 21 may be extended to any length, such as is shown in Figure 1, to provide for the vertical displacement of the ground coils of the heat pump system in order to factilitate filling of the liquid circuit. Although not shown in the present embodiment, the efiiciency of the submerged coil may be improved by the insertion or the forming of fins within the separate sections of serpentine tubing 1&2 to aid in the transfer of heat between the separate sections of serpentine tubing 162 and the liquid disposed about the serpentine tubes 102. Insulation 1111 is disposed about all of the surfaces of the submerged coil 10% to insulate the submerged coil Tilt) from the surrounding air and structure. The short headers 119 of each of the separate sections of serpentine tubing 1412 are connected to a header 121, which is disposed adjacent to the submerged coil 1% behind the wall 31, as can easily be seen in Figures 4 and 2. The lower end of the header 121 is connected to a-tube 124, which is in turn connected to port 57 of the reversing valve St). The other short headers 121) of each of the separate sections of serpentine tubing 102 are each connected to one end of the four lengths of tubing 122. The other ends of each of the four tubes 122 are connected to the submerged sub-cooling coil 130.

The submerged sub-cooling coil 139 is mounted adjacent to the lower portion of the submerged cooling coil 1% by bracket 131, as can easily be seen in Figure 3. For a detailed description of the structure of the submerged subcooling coil 1319 reference is specifically made to Figures 11 and 12. An outer rectangularly shaped case 132 is provided. The casing 132 is divided longitudinally into two portions by a wall 141 mounted within the casing 132. An opening 141 is provided in one end of the wall 141 Sixteen lengths of tithing 135, 136, 137, and 138 are mounted within the casing 132. Eight of the tubes 135 and 136 are mounted on one side of the Wall 1411 Within the casing 132, and the other eight tubes 137 and 138 are mounted on the other side of the wall 149 within the casing 132. The ends of the tubes 135, 136, 137, and 138 project from the ends of the casing 132. Eight curved sections of tubing 139 interconnect the straight sections of tubing 135, 136, 137, and 13S. Specifically the group of four straight tubes 135 are interconnected by four curved sections 139 with the straight sections of tubing 137, and the four straight sections of tubing 136 are interconnected with the four straight sections of tubing 13$ by four curved sections of tubing 139. Tius, eight separate U-shaped tubes are provided which are disposed substantially within the casing 132. At the end of the casing 132 opposite from the end of the casing having the opening 141 therein, two short lengths of tubing 133 and 134 are provided. The short length of tubing 133 is mounted through the casing 132 on one side of the Wall 149, and the short length of tubing 134 is mounted through the casing 132 on the other side of the wall 140. Thus, it can be seen that if a liquid is circulated into one of the short lengths of tubing 133, the liquid will flow through the casing 132 one side thereof to the other end thereof, through the opening 141, along the other side of the wall 141) and out of the short length of tubing 134. It can further be seen that if a refrigerant is caused to flow through the eight U-shaped lengths of tubing, there will be an exchange of heat between the liquid flowing through the casing 132 and the refrigerant within the Ushaped tubes. The connections of the various tubes of the submerged sub-cooling coil 1%) within the heat pump system can be seen in Figures 2, 3, 4, and 5. Adjacent ones of the tubes of groups 135 and 136 are connected together through a Y-shaped element 142 as can be seen in Figure 2. Only one Y-shaped element 142 can be seen in Figure 2 since the remaining three Y-shaped elements are disposed immediately behind the element 142 shown in Figure 2, as can be. seen in Figure 4. Each of the four Y-shaped elements 142 is in turn connected to the four lengths of tubing 122. The other groups of tubes, groups 137 and 138, of the submerged sub-cooling coil 130 are connected to a group of eight capillary tubes 143, each tube of the groups 137 and 138 being connected to a separate one of the eight capillary tubes 143. The other ends of each of the capillary tubes 143 are each connected to one end of each of the eight lengths of tubing forming part of the basement air coil 34, as can easily be seen in Figure 5. Only three are shown as connected in Figure 5 to prevent overcomplication of the drawing, but it is to be understood that the remaining five are connected in a similar manner. Although not shown, the submerged sub-cooling coil 130 may be insulated in a manner similar to that previously described for the submerged cooling coil 100. The short. length. of tubing 134 of the submerged sub-cooling coil 130 is connected to a length of tubing 144. The other end of the length of tubing 144. is connected to the header 111 of the submerged cooling coil 100 as can be seen in Figures 3 and 4. The short length of tubing 133 of'the submerged. sub-cooling coil 130 is connected to one end of a. length of tubing 145, as can be seen in Figures 3 and 4. The other end of the length of tubing 145 is connected tov the. top of a vertical length. of tubing 146, as can be seen in Figure 3. A portion of the vertical length of tubing. 146 has a venturi disposed therein for the circulation of cooling liquid through the water jacket of the compressor 4,0. As described previously the motor 93 is constructed as a unitary structure including a liquid pump disposed at the end thereof opposite from the end having the drive pulley 95 thereon. The inlet 149 to the liquid pump is connected to the header 112 of the submerged cooling coil 100 by a length of tubing 151 as can be seen in Figure 4. The outlet 150 of the liquid pump. is connected to another length of vertical tubing 147, which is disposed adjacent the length of vertical tubing 146, by a length of tubing 148, as can be seen in Figures 3 and 4. It is intended that the vertical tubes 146 and 147 be connected to a series of ground coils disposed within the ground without the residence such as shown in Figure 1.

The remaining structure of the present invention, not previously described, is designated with the numbers 152, 153, 154, and 155. Structure 152 is a high pressure cutout connected by a tube to the reversing valve 50. The operation of a high pressure cutout, such as high pressure cutout 152, is well known in the art, and therefore, it is suificient to state that the high pressure cutout, will stop the compressor 40, should the pressure Within. the reversing valve 50 adjacent to port 58, rise above. a predetermined pressure. The two structures shown as 154 are running capacitors for the motor of the motor-compressor unit 40. The structure 155 is a starting capacitor assembly for the motor of motor-compressor unit 40. The structure shown. generally as 153 is the electrical control panel and equipment for controlling the operation of the heat pump. The connections between the various electrical components of the heat pump and the control panel necessary for the operation of the heat pump are not shown in detail, since many electrical control circuits serving this purpose are well. known in the art, and any one of them may be applied to the present invention.

Before turning to a detailed description of the operation of the present invention, the various circuits of the heat pump will be noted. Turning first to a description of the ground coil liquid circuit of the heat pump, reference is made to Figures 1, 2, 3, 4, and 8'. Assuming that the vertical tubes 146 and 147 are connected to the ground coil 26 through the pair of tubes 27. A liquid, such as a Water-alcohol mixture may be used within this circuit.

I general terms.

To initially charge the ground coil circuit with the wateralcohol, the expansion tank 19 is lowered to a level coincident with the top of the ground cooling coils 26. The cap is removed from. the capped filler tube 21 and as much water-alcohol, as can be introduced, is poured into the system through the tiller tube 21. The liquid pump is then started to force the water-alcohol mixture through the system. The air Within the system will then bubble therefrom, and additional water-alcohol is poured into the filler tube 21 until all of the bubbling ceases. The temperature of the water-alcohol is then taken and an amount of water-alcohol is then poured into the expansion tank 19, the amount dependent upon the possible expansions and contractions of the water-alcohol circuit from the volume at the measured temperature. The filler tube 21 is then capped and the expansion tank 19 is raised and mounted in a position near the ceiling of the basement 13. The entire ground coil circuit plus a portion of the expansion tank 19 will then. be completely filled with the water-alcohol mixture. Now if the liquid pump is operated, water-alcohol will be forced through tubing 147 and 148 into one portion of the tubing 27,. and from there into and through the ground coil 26. If the wateralco-hol flowing through the ground coil is colder than the ground with which the ground coil 26 is in thermal contact, a heating of the water-alcohol will result. If the water-alcohol within the ground coil 26 is warmer than the ground with which the ground coil 26 is in thermal contact, then a cooling of the water-alcohol will result. The water-alcohol will then proceed from the ground coil 26 through the other portion of the tubing 27, and through the tubing 146. As the water-alcohol flows through the tubing 146, a portion of the wateralcohol will flow through the tubing 42, through the water jacket of the motor-compressor 40, and through the tubing 41 to the venturi disposed within the tubing 146. The water-alcohol will then proceed through the tubing 145,. into and through the. submerged sub-cooling coil 130, through the tubing 144, into and through the submerged coil 100, through the tubing 151, and back to and. into the liquid pump.

Turning next to a reference of the refrigerant circuit, reference is made to Figures 2, 3, 4, 5, and 6 or 7. The refrigeration circuitis charged with any of the refrigerants well known in the art, such as one of the Freons. The refrigerant is compressed and discharged from the compressor 40 through the tubing 67. The tubing 67 is connected to the reversing valve 50 and from there may take two courses depending upon the operated position of the reversing valve 50. The suction line 66 of the compressor 40 is also connected to the reversing valve 50. The header 121 of the submerged coil is connected to the reversing valve by means of the tubing 124. Assuming the operated position of the reversing valve 50 wherein the handle 53 is moved to the horizontal position, after passing through the header 121, the refrigerant will then flow through the submerged coil 100 and into the four lengths of tubing 122. From the tubing 122 the refrigerant will flow through. the eight U-shaped tubes of the submerged sub-cooling coil 130, and from the submerged sub-cooling coil into and through the eight capillary tubes 143. From the eight capillary tubes 143 the refrigerant will then. flow through the eight passes of the basement air coil 34, through the connecting tubes 36, into and through the eight balancing receivers 35, into and through the eight lengths of tubing 37, and into and through the eight passes of the main air coil 70, through the header 71, and into and through the tubing 72 to the header 68 which is connected to the reversing valve 50. The specific direction of flow of the refrigerant described is unimportant at this point, but it was selected merely to show the completed paths of the refrigerant.

The remaining important circuits to be noted are the air circuits which have been described previously in To specifically describe the air circuits through the heat pump, reference is made to Figures 1, 2, 3, 4, and 5. Assuming that the heat pump is connected into an arrangement such as shown in Figure 1, the first circuit pertains to the basement air which will be drawn through the basement air coil 34, past the receivers 35, upwards through the compartment defined by the outer walls of the heat pump cabinet and the walls 31, 32, and 33, and out of the upper portion of the heat pump cabinet past the fan 33, and into the basement. Of the main circuit, air will be drawn from the duct 24 into the rear of the heat pump cabinet, through the main air coil 70, upwards past the various structures within the heat pump cabinet, into the openings in both sides 31 of the circulating fan 80, out of the top 82 of the circulating fan 80, and into the duct 25, through the main living space 11 and back to and through the duct 24.

Having described the detailed structure and the various completed circuits of the present invention, the detailed operation thereof will now be described. For a discussion of the detailed operation of the present invention during the cooling cycle reference is made to Figures 1, 2, 3, 4, 5, and 6. First, the reversing valve 50 must be operated to the other position from that shown in Figure 2. The handle 53 of the reversing valve 50 will then be moved to a horizontal position and, as previously described, port 56 will be interconnected through the reversing valve to port 55, and port 57 will be interconnected through the reversing valve to port 53. The motor 93, the compressor 43, and the fan motor 39 are then caused to operate. The latter three components need not be started simultaneously, but may, as is well known in the art, be staggered in starting. The refrigerant will then be compressed by the compressor 4%, caused to flow through the outlet 48, into and through the tubing 67 to port 58 of the reversing valve 50. The warm compressed refrigerant will then flow through the body of the reversing valve 5* through the port 57, into and through the tubing 124, into and through the header 121 of the submerged coil Within the submerged coil 10!), the warm compressed refrigerant will be cooled and condensed to a liquid. The condensed liquid will then flow through the four lengths of tubing 122, into and through the submerged sub-cooling coil 130, wherein the liquid refrigerant will be cooled. From the submerged subcooling coil 139 the cooled liquid refrigerant will flow through the eight capillary tubes 143 to and through the basement air coil 34. The liquid refrigerant will then flow through the eight tubes 36, into and through the eight balancing receivers 35, into and through the eight tubes 37, and into the main air coil '70. The basement air coil 34, the balancing receivers 35, and the main air coil 7t) will be substantially filled with the liquid refrigerant. The air moving through the basement air coil 34 and through the main air coil 70 will cause heat to be transferred to the liquid refrigerant disposed within these coils, meanwhile cooling the air passing therethrough. As the liquid refrigerant is heated, it will assume a gaseous state, and the refrigerant gases will then flow into the header 71. From the header 71 the gaseous refrigerant will flow downward into and through the tube 72, into the header 63, through the body of the reversing valve 50, through the suction line 66 and into the compressor 40 to thereby complete the cycle. The vertical displacement of the various portions of the system shown in Figure 6 is intended to be accurate. Therefore, the refrigerant upon entering the submerged coil 1% from the header 12 will flow in a downward direction through. the submerged coil 190, and downward to and through the submerged subcooling coil 130. Further, the liquid refrigerant will flow downward through the capillary tubes 143 into the basement air coil 34. Also, each portion of the liquid refrigerant that enters the basement air coil 34 will flow in a generally downward direction to the outlet therefrom, and in a generally upward direction through each of the tubes 36, receivers 35, and tubes 37, to the main air coil 70. Further, each portion of the refrigerant upon entering the main air coil 7t) will flow in an upward direc tion to the header 71. The lower end of each of the coil sections of the main air coil 70 are substantially at the same height as the corresponding upper ends of each of the coil sections of the basement air coil 34. Thus, it may first be seen that no liquid refrigerant will flow into the header 71, through the tubings '72 and 66 and into the section side of compressor 40, and further, when the reversing valve 50 is operated to the heating position to cause the tubes 124 and 66 to become the suction line of the compressor 40, no liquid refrigerant will be sucked from the submerged coil 130 into the motor compressor 40. During the cooling cycle the capillaries 143, the basement air coil 34, the receivers 35 and the main air coil 70 will be substantially filled with liquid refrigerant, except for a small volume of the gases which will be bubbling therefrom into the header 71. Meanwhile the submerged coil and the submerged sub-cooling coil will be substantially empty of liquid refrigerant, except for the liquid refrigerant which has condensed therein and has not yet drained into the capillary tubes 143. It can further be seen that the basement air coil 34, the receivers 35 and the main air coil 70 are acting as evaporators, while the submerged coil 1% and the submerged sub-cooling coil 139 are acting as condensers. Meanwhile the ground coil circuit will be operating since the liquid pump is operating, and as previously described, the wateralcohol mixture flowing through the submerged subcooling coil 130 and submerged coil 100 will be heated therein, and this heated water-alcohol Will be caused to flow into the ground coils 27, wherein the heat will be conducted to the ground. Further, fan 38 will be operatlog to cool the basement of the residence, and fan 80 will be operating to cool the main living space 11 of the residence. A thermostat (not shown) may be positioned within the main living space and connected to the electrical control circuits for the heat pump to control the starting and stopping of the heat pump.

For a detailed description of the operation of the heat pump during the heating cycle, reference is made to Figures l, 2, 3, 4, 5, 7, and 8. To operate the heat pump on the heating cycle the reversing valve 50 is operated by the handle 53 to the position shown in Figure 2, wherein port 55 is in communication with port 57 through the body of the reversing valve 50, and port 58 is in communication with port 59 through the body of the reversing valve 50. Referring particularly to Figure 7, the direction of flow of the refrigerant during the heating cycle is generally shown therein by the direction of the arrows. It may be noted that the fan 38 and the fan 80 continue to operate to cause the same air circulation paths as previously described. Also, the liquid pump operates to cause the water-alcohol to flow through the water-alcohol circuit in the same direction as previously described. The only path which has been changed is that of the refrigerant, as particularly shown in Figure 7. During the heating cycle the compressor 40 discharges warm compressed refrigerant into and through tube 67, through port 58, through port 59, through the header 68, through the tubing 72 and through the header 71 into the main air coil 76. The warm gaseous refrigerant will then flow in a generally downward direction through the various tubing convolutions of the main air coil '70, through the eight lengths of tubing 37, through the balancing receivers 35, -to the eight lengths of tubing 36, The air passing through the main air coil 70 will be heated by the warm gaseous refrigerant disposed within these coils. The fan 39 will operate to move this warm air through the main living space of the residence to heat this area. The warm gaseous refrigerant within the balancing receivers 35, and the main air coil 70 will be cooled, and will condense upon the transfer of an amount of heat equal to its latent heat of condensation to the air passing through these coils. The condensed refrigerant will then flow through the eight lengths of tubing 35, and into and through the basement air coil 34. The air passing through the basement air coil 34 Will be heated by the condensed refrigerant Within this coil, and in turn, will cause the refrigerant to be cooled. The fan 38 will operate to move this warm air through the basement to heat it. The cooled and condensed refrigerant will then flow upward through the eight lengths of capillary tubing 143, into and through the submerged sub-cooling coil 13G. Upon passing through the submerged sub-cooling coil 130, the cooled liquid refrigerant will be heated by the wateralcohol passing through the submerged sub-cooling coil 139. The liquid refrigerant will further flow through the four lengths of tubing 122 into the submerged coil 100. The liquid refrigerant within this coil will also be heated by the water-alcohol flowing therethrough from the ground coils 26. As the liquid refrigerant within the submerged sub-cooling coil 130 and the submerged coil 100 is heated to a gaseous state, the gases formed thereby will bubble therefrom and into the header 121. From the header 121, the gaseous refrigerant will flow downward into and through the tubing 124, through port 57, through port 55, through tubing 66, into the compressor 40 to complete the heating cycle. During the heating cycle the submerged sub-cooling coil 130 and the submerged coil 100 are standing substantially full of liquid refrigerant except for a small amount, about twenty per cent, consisting of the gas which is flowing into the header 121. The basement air coil will also contain a substantial amount of liquid refrigerant. The amount of refrigerant selected to charge the heat pump is that amount which will fulfill the latter mentioned condition, that of permitting the submerged sub-cooling coil 130 and the submerged coil 106 to remain substantially full of liquid refrigerant during the heating cycle. It should be noted at this point that as previously described, during the cooling cycle, the submerged sub-cooling 130 and the submerged coil ltit) where substantially empty of liquid refrigerant, and the basement air coil 34, the balancing receivers 35, and the main air coil 70 Where substantially full of liquid refrigerant. The volumes of the balancing receivers 35 are so selected as to fulfill this condition, in other words, that condition wherein the balancing receivers 35, and the main air coil 70 Will hold, during the cooling cycle, all of the liquid refrigerant that was within the submerged sub-cooling coil 130 and the submerged coil W0, during the heating cycle. Returning to the operation of the present invention during the heating cycle, it may thus be seen that the submerged sub-cooling coil 130 and the submerged coil 100 are performing the function of evaporators, and the basement air coil 34, the balancing receivers 35, and the main air coil 70 are performing the function of condensers. It may further be noted that due to the vertical displacement of the various components, no liquid refrigerant will be sucked into the suction lines 124 and 66 during the heating cycle, and if the reversing valve 50 is moved to the cooling position no liquid refrigerant will be sucked into the lines 72 and 66, since the header 71 is free of liquid refrigerant.

The volume of the submerged sub-cooling coil 130, plus the volume of the submerged coil 100 in relation to the volume of the receivers 35, plus the main air coil 70 has been previously discussed. It is important at this point to discuss the relative volumes between the submerged subcooling 130 and the submerged coil 100, and between the basement air coil 34, the receivers 35, and the main air coil 70. The volume of the submerged subcooling coil 13% is substantially less than the volume of the submerged coil 100. Therefore, on the cooling cycle practically all of the gaseous refrigerant will be condensed within the submerged coil100 and the condensed refrigerant will be subcooled by the submerged sub-cooling coil 13%). During the heating cycle, most of the liquid refrigerant will be heated within the submerged coil and a small amount of heating will take place within the submerged sub-cooling coil 130. Thus, on the cooling cycle the submerged sub-cooling coil will sub-cool the liquid refrigerant to increase the efiiciency of the heat pump, and on the heating cycle the submerged sub-cooling coil 130 will aid the efiiciency of the heat pump by a small amount of heating of the liquid refrigerant.

The basement air coil 34 is substantially smaller in volume than the main air coil 76. Also, the fan 38 is of the propeller type and is driven by a small motor, therefore, a proportionately smaller volume of air is moved through the basement air coil 34 than is moved through the main air coil 70. It has been found that about onehalf as much air is moved through the basement air coil 34 as is moved through the main air coil 70 in any given period of time. However, because of the specific constructions described previously, the power acquired to move the air through the basement air coil 34 is onequarter of the amount of power required to move the air through the main air coil 70. This results in a more economical operation of the basement air circuit in comparison to the main air circuit. On the cooling cycle a substantially smaller amount of cooling of air is effected through the basement air coil 34 than through the main air coil 70. However, because the heat load of the basement is generally not as great as the heat load of the portion of the residence above the ground, comparable cooling is not needed in the basement. Thus, it has been found that with this arrangement the basement air is maintained at a substantially cool and comfortable temperature. Further, it has been found that dehumidification of the basement air is substantial, and entirely sulficient under all normal circumstances. This excellent dehumidification of the basement air is partially due to the fact that during the cooling cycle the basement air coil surfaces are colder than the surfaces of the main air coil 70. The balancing receivers, although substantial in volume, have a small effect as heat exchangers because of the minimum area for heat conduction. During the heating cycle, substantially all of the liquid refrigerant is condensed within the main air coil 70; however, it has been found that the liquid refrigerant may be cooled, or may heat that basement air, to such a degree as to efiiciently heat the basement air to a warm and comfortable temperature. During the heating cycle, the basement air is heated by heat derived from sub-cooling the condensed refrigerant in the basement air coil 34, the refrigerant having been condensed within the main air coil 70. Therefore, heat is secured for the basement air circuit without any increase in the load on the motorcompressor unit 40. This further increases the economy of the basement air circuit in comparison to the main air circuit.

Having described the invention what is considered new and desired to be protected by Letters Patent is:

1. In combination with a building having two enclosed spaces, the first of said spaces having a substantially greater heating and cooling load than the second of said spaces, a heat pump mounted in said second space, said heat pump comprising two compartments, and air-refrigerant heat exchanger mounted within the first of said two compartments, means mounted within said first compartment for circulating air from said second space through said air-refrigerant heat exchanger, a duct system connecting the second of said two compartments to said first space, a second air-refrigerant heat exchanger mounted within said second compartment, means mounted within said second compartment for circulating air from said first space through said second air-refrigerant heat exchanger, said second air-refrigerant heat exchanger having a substantially greater capacity than said first airrefrigerant heat exchanger, tubing means connecting the refrigerant portions of said first and second air-refrigerant heat exchangers in series, means selectively operable to one position for supplying a gaseous refrigerant to said refrigerant portion of said second heat exchanger and for drawing liquid refrigerant from said refrigerant portion of said first heat exchanger, whereby said gaseous refrigerant supplied to said second heat exchanger is condensed therein to heat the air passing therethrough, and the condensed refrigerant then being supplied to said first heat exchanger wherein the liquid refrigerant is cooled to heat the air passing therethrough, said last mentioned means selectively operable to another position for supplying cooled liquid refrigerant to said refrigerant portion of said first heat exchanger and for drawing gaseous refrigerant from said refrigerant portion of said second heat exchanger, whereby said cooled liquid refrigerant supplied to said first heat exchanger is heated therein to cool theair passing therethrough and the liquid refrigerant then being supplied to said second heat exchanger wherein the liquid refrigerant is evaporated to cool the air passing therethrough.

2. In a heat pump system for mounting in a building having two enclosed spaces, wherein one of the two enclosed spaces has a substantially smaller heating and cooling load than the second of said spaces, two compartments mounted within said heat pump system, an airrefrigerant heat exchanger mounted within the first of said two compartments, means mounted within said first compartment for circulating air from said first space through said air-refrigerant heat exchanger, a duct system connected to the second of said two compartments and connectible to said second space, a second air-refrigerant heat exchanger mounted within said second compartment, means mounted within said second compartment for circulating air from said second space through said duct system and through said second air-refrigerant heat exchanger, said second air-refrigerant heat exchanger having a substantially greater capacity than said first air-refrigerant heat exchanger, tubing means connecting the refrigerant portions of said first and second air-refrigerant heat exchangers in series, means selectively operable to one position for supplying a gaseous refrigerant to said refrigerant portion of said second heat exchanger and for drawing liquid refrigerant from said refrigerant portion of said first heat exchanger, whereby said gaseous refrigerant supplied to said second heat exchanger is condensed therein to heat the air passing therethrough, and the condensed refrigerant then being supplied to said first heat exchanger wherein the liquid refrigerant is cooled to heat the air passing therethrough, said last mentioned means selectively operable to another position for supplying cooled liquid refrigerant to said refrigerant portion of said first heat exchanger and for drawing gaseous refrigerant from said refrigerant portion of said second heat exchanger, whereby said cooled liquid refrigerant supplied to said first heat exchanger is heated therein to cool the air passing therethrough, and the liquid refrigerant then being supplied to said second heat exchanger wherein the liquid refrigerant is evaporated to cool the air passing therethrough.

3. In combination with a building having two enclosed spaces, the first of said spaces having a substantially greater heating and cooling load than the second of said spaces, a heat pump mounted in said second space, said heat pump comprising two compartments, an air-refrigerant heat exchanger mounted within the first of said two compartments, means mounted within said first compartment for circulating air from said second space through said air-refrigerant heat exchanger, a duct system connecting the second of said two compartments to said first space, a second air-refrigerant heat exchanger mounted within said second compartment, means mounted within said second compartment for circulating air from said first space through said second air-refrigerant heat exchanger, said second air-refrigerant heat exchange having a stantially greater capacity than said first air-refrigerant heat exchanger, tubing means interconnecting the refrigerant portions of said first and second heat exchangers, a liquid-refrigerant heat exchanger mounted within said heat pump, a ground coil heat exchange system disposed Within the ground without said building, second tubing means interconnecting the liquid portion of said liquidrefrigerant heat exchanger and said ground coil heat exchange system, a liquid disposed within and completely filling said liquid portion of said liquid-refrigerant heat exchanger, said second tubing means, and said ground coil system, means for circulating said liquid, metering devices connecting the refrigerant portions of said liquidrefrigerant heat exchanger and said first air-refrigerant heat exchanger in series, means selectively operable to one position for supplying a gaseous refrigerant to said refrigerant portion of said second heat exchanger and for drawing gaseous refrigerant from the refrigerant portion of said liquid-refrigerant heat exchanger, whereby said gaseous refrigerant supplied to said second heat exchanger is condensed therein to heat the air passing therethrough, and the condensed refrigerant then being supplied to said first heat exchanger wherein the liquid refrigerant is cooled to heat the air passing therethrough, and the cooled liquid-refrigerant then being supplied to said metering devices wherein said cooled liquid refrigerant is then metered to the refrigerant portion of said liquidrefrigerant heat exchanger and whereby said liquid refrigerant metered to said liquid-refrigerant heat exchanger is evaporated therein to cool the liquid passing therethrough, said last mentioned means selectively operable to another position for supplying gaseous refrigerant to the refrigerant portion of said liquid-refrigerant heat exchanger and for drawing gaseous refrigerant from said refrigerant portion of said second heat exchanger, whereby said gaseous refrigerant supplied to the refrigerant portion of said liquid-refrigerant heat exchanger is condensed therein to heat the liquid passing therethrough, and the condensed refrigerant then being supplied to said metering devices wherein said liquid refrigerant is metered to said first heat exchanger, whereby said liquid refrigerant metered to said first heat exchanger is heated therein to cool the air passing therethrough, and the liquid refrigerant then being supplied to said second heat exchanger wherein said liquid refrigerant is evaporated to cool the air passing therethrough.

4. In a heat pump system for mounting in a building having two enclosed spaces, wherein one enclosed space of said two enclosed spaces has a substantially smaller heating and cooling load than the second of said two spaces, two compartments mounted within said heat pump system, an air-refrigerant heat exchanger mounted within the first of said two compartments, means mounted within said first compartment for circulating air from said first space through said air-refrigerant heat exchanger, a duct system connected to the second of said two compartments and connectible to said second space, a second air-refrigerant heat exchanger mounted within said second compartment, means mounted within said second compartment for circulating air from said second space through said duct system and through said second airrefrigerant heat exchanger, said second air-refrigerant heat exchanger having a substantially greater capacity than said first air-refrigerant heat exchanger, tubing means interconnecting the refrigerant portions of said first and second air-refrigerant heat exchangers in series, a liquid-refrigerant heat exchanger mounted within said heat pump system, a ground coil heat exchange system disposable within the ground without said building, second tubing means interconnecting the liquid portion of said liquid-refrigerant heat exchanger and said ground coil heat exchange system, a liquid disposed within and completely filling said liquid portion of said liquid-refrigerant heat exchanger, said second tubing means, and said ground coil system, means for circulating said liquid,

metering devices connecting the refrigerant portions of said liquid-refrigerant heat exchanger and said first airrefrigerant heat exchanger in series, means selectively operable to one position for supplying a gaseous refrigerant to said refrigerant portion of said second heat exchanger and for drawing gaseous refrigerant from the refrigerant portion of said liquid-refrigerant heat exchanger, whereby said gaseous refrigerant supplied to said second heat exchanger is condensed therein to heat any air passing therethrough, and the condensed refrigerant then being supplied to said first heat exchanger wherein the liquid refrigerant is cooled to heat any air passing therethrough, and the cooled liquid refrigerant then being supplied to said metering devices wherein said cooled liquid refrigerant is metered to the refrigerant portion of said liquid-refrigerant heat exchanger and whereby said liquid refrigerant metered to said liquidrefrigerant heat exchanger is evaporated therein to cool the liquid passing therethrough, said last mentioned means selectively operable to another position for supplying gaseous refrigerant to the refrigerant portion of said liquid-refrigerant heat exchanger and for drawing gaseous refrigerant from said refrigerant portion of said second heat exchanger, whereby said gaseous refrigerant supplied to the refrigerant portion of said liquid-refrigerant heat exchanger is condensed therein to heat the liquid passing thcrethrough, and the condensed refrigerant then being supplied to said metering devices wherein said liquid refrigerant is metered to said first heat exchanger, whereby said liquid refrigerant metered to said first heat exchanger is heated therein to cool any air passing therethrough, and the liquid refrigerant then being supplied to said second heat exchanger wherein said liquid refrigerant is evaporated to cool any air passing therethrough.

5. In a heat pump system, a plurality of at least four heat exchange units, a metering device, a plurality of tubes, a portion of said plurality of tubes connecting a group of said heat exchange units in series and connecting one end of said series to one end of said metering device, the remainder of said tubes connecting a second group of said heat exchange units in a second series and connecting one end of said second series to the other end of said metering device, a compressor, a certain amount of liquid refrigerant disposed within said system, means selectively operable to one position for connecting said compressor between both of the other ends of said series to cause a flow of said refrigerant in one direction through said system and operable to another position for connecting said compressor between both of the other ends of said series to cause a flow of said refrigerant in another direction through said system when said compressor is operated, said heat exchange units formed to have volumes whereby said first group of heat exchange units are substantially full of said liquid refrigerant and said second group of heat exchange units are substantially empty of said liquid refrigerant when said means are operated to said one position and said Compressor is operated, and whereby said first group of heat exchange units are substantially empty of saidliquid refrigerant and said second group of heat exchange units are substantially full of said liquid refrigerant from said first group of heat exchange units when said means are operated to said other position and said compressor is operating.

6. In a heat pump system, a plurality of at least four heat exchange units, a metering device, a plurality of tubes, a portion of said plurality of tubes connecting a group of said heat exchange units in series and connecting one end of said series to one end of said metering device, the remainder of said tubes connecting a second group of said heat exchange units in a second series and connecting one end of said second series to the other end of said metering device, a compressor, a certain amount of refrigerant disposed within said system, means selectively operable to one position for connecting said compressor between both of the other ends of said series to cause a flow of said refrigerant in one direction through said system and operable to another position for con-' necting said compressor between both of the other ends of said series to cause a flow of said refrigerant in another direction through said system when said compressor is operated, said heat exchange units formed to have volumes whereby said first group of heat exchange units and one of said heat exchange units of said second group of heat exchange units are substantially full of said liquid refrigerant and the other heat exchange units of said second group of heat exchange units are substantially empty of said liquid-refrigerant when said means are operated to said one position and said compressor is operated, and whereby said first group of heat exchange units are substantially empty of said liquid refrigerant and said second group of heat exchange units are substantially full of said liquid refrigerant when said means are operated to said other position and said compressor is operating.

7. In a heat pump system, four exchange units, a metering device, a balancing receiver, a plurality of tubes, a portion of said plurality of tubes connecting two of said four heat exchange units in series and connecting one end of said series to one end of said metering device, the remainder of said tubes connecting the other two of said four heat exchange units and said balancing receiver in a second series and connecting one end of said second series to the other end of said metering device, a compressor, a refrigerant disposed within said system, means selectively operable to one position for connecting said compressor between the other ends of said series to cause a how of said refrigerant in one direction through said system and operable to another position for connecting said compressor between the other ends of said series to cause a flow of said refrigerant in another direction through said system when said compressor is operated, said four heat exchange units and said balancing receiver formed to have volumes whereby said two of said four heat exchange units and one of said other two of said four heat exchange units are substantially full of said liquid refrigerant, and said balancing receiver and the second of said other two of said four heat exchange units are substantially empty of said liquid refrigerant when said means are operated to said one position and said compressor is operated, and whereby said two heat exchange units of said four heat exchange units are substantially empty of said liquid refrigerant, and said other two of said four heat exchange units and said balancing receiver are substantially full of said liquid refrigerant when said means are operated to said other position and said compressor is operating.

8. In a heat pump system charged with a refrigerant, a plurality of at least four heat exchange units, a metering device, a plurality of tubes, a portion of said plurality of tubes connecting a group of said heat exchange units in series and connecting one end of said series to one end of said metering device, the remainder of said tubes connecting a second group of said heat exchange units in a second series and connecting one end of said second series to the other end of said metering device, said first group of heat exchange units formed to have a total volume equal to the total volume of said second group of heat exchange units, so that when the other ends of both of said series are connected in one direction in a heat pump system, said first group of heat exchange units will be substantially full of liquid refrigerant and said second group of heat exchange units will be substantially empty of liquid refrigerant, and so that when said other ends of both of said series are connected in said heat pump system in another direction said second group of heat exchange units will be substantially filled by the liquid refrigerant from said first group of heat exchange units and said first group of heat exohange' units will be substantially empty of liquid refrigerant.

9. In a heat pump system charged with a refrigerant, three heat exchange units, a balancing receiver, a metering device, a plurality of tubes, a portion of said plurality of tubes connecting the first and second of said three heat exchange units in series and connecting one end of said series to one end of said metering device, the remainder of said tubes connecting said balancing receiver' and the third of said three heat exchange units in a second series and connecting one end of said series to the other end of said metering device, said three heat exchange units and said balancing receiver formed to have volumes whereby the total volume of said first and second of said three heat exchange units is equal to the total volume of said balancing receiver and said third of said three heat exchange units, so that when the other ends of said series are con nected in one direction in said heat pump system said first and second heat exchange units will be substantially full of liquid refrigerant and said third heat exchange unit and said balancing receiver will be substantially empty of liquid refrigerant, and so that when said other ends of said series are connected in said heat pump system in another direction said third heat exchange unit and said balancing receiver will be substantially filled by the liquid refrigerant from said first and second heat exchange units and said first and second heat exchange units will be substantially empty of liquid refrigerant.

10. In a heat pump system charged with a refrigerant, four heat exchange units, a balancing receiver, a plurality of tubes, a portion of said plurality of tubes connecting the first and second of said heat exchange units in series and connecting one end of said series to one end of said metering device, the remainder of said tubes connecting the third and fourth of said heat exchange units and said balancing receiver in a second series and connecting one end of said second series to the other end of said metering device, said first and second heat exchange units positioned above said third and fourth heat exchange units and said balancing receiver, said fourth heat exchange unit and said balancing receiver positioned substantially, vertically above said third heat exchange unit, said first and second heat exchange units formed to have a total volume equal to the total volume of said fourth heat exchange unit and said balancing receiver, so that when the other ends of both of said series are connected in one direction in a heat pump system said first, second and third heat exchange units will be substantially full of liquid refrigerant and said balancing receiver and said fourth heat exchange unit will be substantially empty of liquid refrigerant, and so that when said other ends of both of said series are connected in said heat pump system in another direction said first and second heat exchange units will be substantially empty of liquid refrigerant and said balancing receiver and said third and fourth heat exchange units and said balancing receiver will be substantially full of liquid refrigerant.

11. In a heat pump system, a first heat exchanger comprising a vertically convoluted coil, 21 second heat exchanger comprising a coil entirely disposed within a horizontal plane, one end of said second heat exchange unit being connected to the lower end of said first heat exchange unit, a metering device, one end of said metering device connected to the other end of said second heat exchange unit, third and fourth heat exchange units, said third and fourth heat exchange units comprising vertically convoluted coils, a balancing receiver, said third and fourth heat exchange units and said balancing receiver positioned within said system below said first and second heat exchange units, the other end of said rnetering device connected to the upper end of said third heat exchange unit, the vertically convoluted coil of said fourth heat exchange unit positioned substantially above said third heat exchange coil, said balancing receiver connected between the lower end of said third exchange unit and the lower end of said fourth heat exchange unit, a compressor, valve means selectively operable to one position for connecting said compressor in one direction between the upper end of said first heat exchange unit and the upper end of said fourth heat exchange unit and operable to another position for connecting said compressor in an other direction between the upper end of said fourth heat exchange unit and the upper end of said first heat exchange unit, a certain amount of liquid refrigerant disposed within said system, said heat exchange units further formed to have volumes whereby said first, second, and third heat exchange units are substantially full of said liquid refrigerant and said balancing receiver and said fourth heat exchange unit are substantially empty of said liquid refrigerant when said means are operated to said one position and said compressor is operated, and whereby said first and second heat exchange units are substantially empty of said liquid refrigerant and said balancing receiver and said third and fourth heat exchange units are substantially full of said liquid refrigerant when said means are operated to said other position and said compressor is operating.

12. In a heat pump system, four heat exchangers, the first, third and fourth of said four heat exchangers comprising a plurality of vertically disposed vertically convoluted coils, the second of said four heat exchangers comprising a plurality of coils substantially disposed within a horizontal plane, a plurality of balancing receivers, one end of each of said coils of said second heat exchanger being connected to the lower ends of each of the vertically convoluted coils of said first heat exchanger, a plurality of metering devices, one end of each of said metering devices connected to the other end of each of said coils of said second heat exchanger, the other end of each of said metering devices connected to the upper ends of each of the vertically convoluted coils of said third heat exchanger, one end-of each of said balancing receivers connected to the lower ends of each of the vertically convoluted coils of said third heat exchanger, the other ends of each of said balancing receivers connected to the lower ends of each of the vertically convoluted coils of said fourth exchanger, two vertically disposed headers, the first of said headers connected to the upper end of each of said vertically convoluted coils of said first heat exchanger, the second of said headers connected to the upper end of each of the vertically convoluted coils of said fourth heat exchanger, whereby said headers may be connected in said system in one direction whereby gaseous refrigerant is delivered to said first heat exchanger and withdrawn from said fourth heat exchanger, whereby gaseous refrigerant will be condensed to a liquid within said first heat exchanger and caused to flow by gravity to said second heat exchanger, and whereby said headers are connectible in said system in another direction whereby gaseous refrigerant is delivered to said second header and withdrawn from said first header, and whereby no liquid refrigerant will be drawn from said headers, so that selectively said first and second heat exchangers may be operated as condensers and said third and fourth heat exchangers may be operated as evaporators.

13. In a heat pump system for use in two enclosed spaces wherein one of the enclosed spaces has a higher heat load than the other and wherein said system is mounted in said other enclosed space, first and second heat exchangers connected in series, said first heat exchanger having a substantially greater volume than said second heat exchanger, means for introducing a gaesous refrigerant into said first heat exchanger, means for drawing liquid refrigerant from said second heat exchanger, duct means interconnecting said first heat exchanger and said one enclosed space, centrifugal fan means for circulating air through said first heat exchanger and through said one enclosed space, whereby said gaseous refrigerant is cooled to the temperature at which said gaseous refrigerant condenses, propeller fan means of a size substantially smaller than said centrifugal fan means for circulating airthrough'said secondheat exchanger and directly through-the otherenclosedspace whereby the condensed refrigerant is cooled.

14. In a heat pump system, a heat exchanger for increasing the efliciency of said heat pump system, said heat exchanger comprising a longitudinal casing, a plurality of walls disposed transversely within said casing thereby dividing said casing internally into three compartments, a second plurality of walls, said second plurality of walls mounted transversely within said casing in each of said compartments, and positioned in a parallel spacedapart relationship from each other and from said first plurality of walls, each of said second plurality of walls having a hole ,thcrethrough, said second plurality of walls further arranged so that adjacent walls have said holes positioned at the opposite ends thereof, whereby a separate and continuous passageway is formed through each of said compartments, one of the outer walls of said casing having a plurality of openings therethrough, said openings through said outer wall positioned in pairs, one pair for each compartment, and each opening of said pair located at :one .end of said passageway through said compartment, a pair of headers, one of said pair of headers connected to one opening of each of said pair of openings in each compartment, the other of said headers connected to the other opening of each of said pair of openings through said compartments, a plurality of straight lengths of tubing, said straight lengths of tubing mounted to extend longitudinally through said casing and said first and second pluralities of walls, said straight lengths of tubing further mounted in rows in a vertically staggered relationship, a plurality of arcuateshaped tubings, said arcuate-shaped tubings interconnecting adjacent ones of said straight lengths of tubing in groups so that a plurality of serpentine coils are formed, the two outer surfaces of said casing which are parallel to said straight lengths of tubing further formed to be corrugated, the corrugations of said two outer surfaces of said casing being arranged to conform to the staggered contour of said straight lengths of tubing, whereby a refrigerant may be simultaneously circulated through each of said lengths of serpentine tubing, and whereby a refrigerant may be circulated into one of said headers, through each of said compartments simultaneously, and out of the other of said headers.

15. In a heat pump system, a heat exchanger for said system, said heat exchanger comprising a longitudinal casing, two walls disposed within said casing dividing said casing internally into three compartments, a plurality of second walls, said second walls mounted transversely within said casing in equal numbers in each of said compartments and positioned in a parallel spacedapart relationship from each other and from said two walls, each of said second walls having a hole therethrough, said second walls further arranged so that adjacent walls have said holes positioned at the opposite ends thereof, whereby a separate and continuous serpentine passageway is formed through each of said three compartments, a pair of openings through one of the outer walls of each of said compartments, each opening of each pair of openings located at opposite ends of said passageway through each of said compartments, a pair of headers, one of said pair of headers connected to one opening of each of said pair of openings in each conipartment, the other of said headers connected to the other opening of each of said pair of openings in each compartment, a plurality of at least 112 straight lengths of tubing, said straight lengths of tubing mounted to extend longitudinally through said casing and said two walls and said second walls, said straight lengths of tubing further mounted in rows in a vertically staggered relationship, a plurality of at least 108 arcuate-shaped tubings, said arcuate-shaped tubings interconnecting adjacent ones of said straight lengths of tubing in groups so that four separate serpentine coils are formed, the two outer surfaces of said casing which are parallel to said straight lengths of tubing further formed to be corrugated, the corrugations of said two outer surfaces of said casing being arranged to conform to the staggered contour of said straight lengths of tubing, whereby a refrigerant may be simultaneously circulated through each of said four serpentine coils, and whereby a refrigerant may be circulated into one of said headers, through each of said three compartments simultaneously, and out of the other of said headers.

16. in a heat pump system, a refrigerant compressor charged with a refrigerant and having an outlet line and a suction line, a heat exchanger for said system, said heat exchanger comprising a horizontally disposed longitudinally extending casing, said casing mounted in said system vertically above said compressor, a plurality of vertical walls disposed within said casing dividing said casing internally into three compartments, a second plurality of vertical walls, said second plurality of walls mounted within said casing in each of said compartments and positioned in a parallel spaced-apart relationship from each other and from said first plurality of walls, each of said second plurality of walls having a hole therethrough, said second plurality of walls further arranged so that adjacent walls have said holes positioned at the opposite ends thereof, whereby a continuous passageway is formed through each of said three compartments, said casing provided with three pairs of holes, each pair of holes positioned at the opposite ends of said passageways of each compartment, a pair of headers, one of said pair of headers connected to one opening of each of said pair of openings of each compartment, the other of said headers connected to the other opening of each of said pair of openings of said compartments, means for supplying a cooling medium to one of said headers and withdrawing said medium from the other of said headers, a plurality of straight lengths of tubing, said straight lengths of tubing mounted horizontally to extend longitudinally through said casing and said first and second pluralities of walls, said straight lengths of tubing further mounted in rows in a vertically staggered relationship, a plurality of arcuateshaped tubings, said arcuate-shaped tubings interconnecting adjacent ones of said straight lengths of tubing in groups so that a plurality of vertically disposed serpentine coils are formed, the two outer surfaces of said casing which are parallel to said straight lengths of tubing further formed to be curvilinear, said curvilinear shape of said two outer surfaces of said casing formed to conform to the vertical stagger of said straight lengths of tubing, a vertically disposed header connected to the upper end of each of said serpentine coils, a refrigerant reversing valve connected between the outlet line and the suction line of said compressor and the bottom of said header, said reversing valve selectively operable in one position to connect the outlet line of said compressor to said vertical header and operable in another position to connect the suction line of said compressor to said vertical header, so that when said reversing valve is operated in said one position said outlet line of said compressor is connected to said vertical header and when said medium is caused to flow through said pair of headers, any gaseous refrigerant flowing from said compressor will be cooled and condensed within said serpentine coils and will flow downward therethrough, and so that when said reversing valve is operated in said another position said suction line of said compressor is connected to said header and no liquid refrigerant will be drawn from said serpentine coils into said suction line.

17. In a heat pump system, a heat exchanger for increasing the efliciency of said system, said heat exchanger comprising a longitudinal casing, a wall mounted longitudinally within said casing whereby said casing is internally divided into two compartments, said wall having 

